<template>
  <div class='xtx-carousel' @mouseenter="stop" @mouseleave="restart">
    <ul class="carousel-body">
     <li class="carousel-item" v-for="(item,index) in sliders" :key="index" :class="{fade:activeIndex===index}">
       <RouterLink :to="item.hrefUrl">
         <img v-lazy="item.imgUrl" alt="">
        </RouterLink>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)"><i class="iconfont icon-angle-left"></i></a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)"><i class="iconfont icon-angle-right"></i></a>
    <div class="carousel-indicator">
     <span v-for="(item,index) in sliders" :key="index" :class="{active:activeIndex===index}" @click="activeIndex=index"></span>
    </div>
  </div>
</template>

<script>
import { onUnmounted, ref, watch } from 'vue'
export default {
  name: 'XtxCarousel',
  props: {
    // 数据
    sliders: {
      type: Array,
      default: () => []
    },
    // 持续时间
    duration: {
      type: Number,
      default: 3000
    },
    // 自动播放
    autoPlay: {
      type: Boolean,
      default: false
    }
  },
  setup (props) {
    // 默认显示的图片的索引
    const activeIndex = ref(0)

    // 切换页面
    const toggle = (val) => {
      activeIndex.value += val
      if (activeIndex.value < 0) activeIndex.value = props.sliders.length - 1
      if (activeIndex.value > props.sliders.length - 1)activeIndex.value = 0
    }

    // 自动播放
    let timeId
    const start = () => {
      clearInterval(timeId)
      timeId = setInterval(() => {
        toggle(1)
      }, props.duration)
    }

    // 监听数组有没得数据 有数据并且图片长度大于1和可以自动轮播就开启自动播放
    watch(() => props.sliders, () => {
      if (props.sliders.length > 1 && props.autoPlay) start()
    },
    { immediate: true }
    )

    // 鼠标移入停止自动播放
    const stop = () => {
      clearInterval(timeId)
    }
    // 鼠标移出开启自动播放
    const restart = () => {
      if (props.sliders.length > 1 && props.autoPlay) start()
    }

    // 组件卸载 关闭定时器
    onUnmounted(() => {
      clearInterval(timeId)
    })

    return { activeIndex, toggle, stop, restart }
  }
}
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>
